Globin synthesis will be studied by determinations of incorporation of labeled amino acids into globin chains by erythroid cell in vitro. The studies will seek to define mechanisms that coordinate synthesis of the complementary globin chains of hemoglobin. Erythroid cells for these studies will be obtained from the following: human subjects having hemolytic diseases, patients with thalassemia disorders and thalassemia-hemoglobinopathy syndromes, patients with structurally abnormal hemoglobins, and from animal species having duplicated globin beta-chain loci.